Satellite despin device



P 9, 1969 J. J. MILLY 3,465,986

SATELLITE DESPIN DEVI CE Filed June 7, 1967 4 Sheets-Sheet 1 FIG. I

INVENTOR JOHN JMiLLY c. will ATTORNEYS Sept. 9, 1969 Filed June '7, 1967J. J. MILLY SATELLITE DESPIN DEVICE 4 Sheets-Sheet 2 FIG. 2

INVENTOR JOHN J MILLY ATTORNEYS p 1969 J. J. MILLY 3,465,986

SATELLITE DESPIN DEVICE Filed June 7. 1967 4 Sheets-Sheet 5 FIG.3

INVENTOI? JOHN J. MILLY BY Cf-j f- 'h MC. wel

P 1969 J. J. MILLY 3,465,986

SATELLITE DESPIN DEVICE Filed June 7, 1967 4 Sheets-Sheet 4 FIG. 4

I INVENTOR JOHN J. MILLY BY -J adieu/Z262.

A TTORNE Y5 United States Patent 3,465,986 SATELLITE DESPIN DEVICE JohnJ. Milly, Huntsville, Ala., assignor to the United States of America asrepresented by the Administrator of the National Aeronautics and SpaceAdministration Fiied June 7, 1967, Ser. No. 645,563

Int. Cl. B64g 9/00 US. Cl. 244-1 4 Claims ABSTRACT OF THE DISCLOSURE Agrasping device comprising an extensible boom device connected to apowerhead having a plurality of pivotally mounted arms positionedthereon which are actuated by a spring driven linkage. The arms andlinkage can be cocked and then released by a trigger included in thepowerhead to cause the arms to move to a grasping position. Thepowerhead includes a rotary rocket motor for generating thrust whichtends to contra-rotate the powerhead and stop the rotation of a graspedobject. The powerhead is releasably connected to the extensible boomthat is formed from a roll of thin metallic tape stored on a spool in ahand held deployment device. The metal tape assumes the form of a tubewhen unfurled.

BACKGROUND OF THE INVENTION The invention described herein was made byan employee of the United States Government and may be manufactured andused by or for the Government for governmental purposes without thepayment of any royalties thereon or therefor.

During the past several years, the United States and other countrieshave placed a great many satellites and other objects into orbit aboutthe earth in carrying out their numerous research programs. Some of theobjects placed into space were satellites that were spin stabilized toenable performances of their intended function. Many of the spinning orrotating satellites have completed their intended missions and have longsince ceased to function. Most are now maintaining useless orbits aboutthe earth occupying space, but providing no further research data.

Recently, interest in these vehicles has increased because of thepossibility of their being given inflight maintenance or retrieved forstudy of such things as causes of failure, life expectancy of componentsand the effect of an outer space environment. Information that isobtained can be applied to future space vehicles. Thus, the need existsfor a device to retrieve objects from outer space and particularly,there exists a need for a tool capable of stopping the rotation of asatellite so as to permit an astronaut to work on or retrieve thesatellite without danger of bodily injury. It is readily apparent thatthe consequences of an astronaut grasping a rotating satellite would bedisastrous.

SUMMARY OF THE INVENTION The invention described herein comprises anextensible boom device connected to a powerhead for grasping andstopping the rotation of a satellite in space. The extensible boomdevice is utilized to position the powerhead in the vicinity of thesatellite to be stopped and it is composed of a length of thin metaltape which is wound upon a spool or storage drum mounted in a containerof a convenient size to be held in the hand of an astronaut. Thecharacteristics of the metal tape is such that when unwound from thestorage spool it will assume the form of a tube to which the powerheadcan be attached. The tape is wound or unwound by means of a hand crankor other suitable means connected through appropriate gearing to thestorage spool. The powerhead includes a cylindrical body 3,465,986Patented Sept. 9, 1969 "ice having three arms pivotally mounted to oneend thereof. The arms have grasping pads attached to the extremitiesthereof and the arms actuated by means of a spring powered linkage. Thelinkage can be placed in a cocked position and a trigger mechanism isincluded that is actuated by contact with a satellite to unlock thelinkage and permit the arms to grasp the satellite. A quick disconnectcoupling is provided between the extensible boom and the powerhead.Also, a rotary rocket motor is provided on the powerhead which providesthe force necessary to stop the rotation of a satellite that has beengrasped.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a pictorial view of anastronaut in the process of using a despin tool constructed inaccordance with this invention.

FIGURE 2 is a view similar to FIGURE 1 except that the powerhead hasbeen attached to the satellite and disconnected from the extensibleboom.

FIGURE 3 is a pictorial view,'partially broken away, showing the detailsof the extensible boom device.

FIGURE 4 is a pictorial view, partially in section and broken away,showing the details of the powerhead.

DESCRIPTION OF THE PREFERRED EMBODIMENT Refer now to FIGURE 1 of thedrawings which illustrates how a despin device constructed in accordancewith this invention will be used by an astronaut in space. An astronaut10 has exited from his spacecraft 12 and has deployed a despin device 14towards a rotating satellite 16. In FIGURE 2, powerhead 15 of the despindevice has been attached to the rotating spacecraft and a rotary rocketmotor 18 has been ignited which will generate sufiicient thrust in adirection indicated by arrows 17 in FIGURE 2 to stop the rotation of thesatellite.

Referring now to FIGURE 3 of the drawings, the extensible boom devicefor placing the satellite despin device in the vicinity of a satellitewill be described. The extensible boom device consists of an outerhousing 20 having a handle 22 attached to one end thereof. Housing 20has a storage drum or spool rotatably mounted therein on which a thinmetal tape 24 is stored. The metal tape passes from the storage spoolacross two sets of guide rollers 26 and 28 suitably mounted in thehousing 20 out through guide tube 30 attached to one end of housing 20.The characteristic of the metal tape is such that after it has passedthrough roller set 26, it then as surnes the form of a tube toeffectively form a boom or tube 32 to which a powerhead or despin devicedescribed hereinafter can be attached. The guide rollers 28 function toflatten out the tape when it is being rewound. The storage spool uponwhich the metal tape is stored is suitably journaled within housing 20and can be rotated either by a hand crank 34 and drive pinion 36 or thehand crank can be replaced if desired with a suitable battery drivenelectric motor (not shown).

A trigger mechanism 38 is mounted in handle 22 that engages the storagespool to prevent rotation thereof until released. The connection betweenthe trigger mechanism and the spool is not shown in detail herein sinceany suitable mechanism can be provided to lock the storage spool inplace and prevent rotation thereof until the trigger is released. Themetal tape can be made of any suitable material, thin stainless steelfor example, which will have suflicient strength to extend and retractthe despin device in space. Due to the weightless conditions that existin an outer space environment, the strength of the tube formed by thethin metallic tape will not be a significant factor and the boom can beformed from very lightweight tape.

Referring now to FIGURE 4 of the drawings, powerhead consists of atubular body adapted to have end 42 of the extensible boom inserted intoone end thereof. There is a quick disconnect connection between theextensible boom and tubular body 40 made up of a handle release hook 44which has an eye 46 formed on one end thereof that is mounted on atransverse pin 48 mounted in end 42 of the extensible boom. The otherend of the handle release hook is in the form of a hook which fits overa second transverse pin 50 mounted in housing 40. An unlocking spring 54is attached to end 42 of the extensible boom and is positioned so thatit exerts a bias against the handle release hook that tends to move thehandle release hook to an unlocked position. The extensible boom has aslot 56 formed in end 42 thereof that when fitted over pin 50 preventsrelative rotation of the extensible boom with respect to the powerhead.A disengage spring 58 is positioned within tube 40 so as to abut aretainer pin 60. Compressed spring 58 exerts a force which acts upon aguide disc 62 positioned between the spring 58 and end 42 of theextensible boom.

The force exerted by the spring is such that when the handle releasehook has been unlocked from pin 50, the force exerted by the spring willcause separation of the extensible boom and powerhead. Unlocking of thehandle release hook is accomplished by pushing end 42 of the extensibleboom into the end of tubular body 40 sufliciently far to permit thehooked end of the handle release spring to clear pin 50. The unlockingspring will then displace the hook far enough to clear pin 50 when theextensible boom is separated from the powerhead.

The powerhead has three arm members 64 pivotally mounted thereon whichfunction to grasp an object. The arm members and linkage associated witheach are identical and therefore only one arm member will be describedherein. Each arm member 64 includes two parallel links 66 and 68 thatare connected at their extremities by brackets 70 and 72. Each of thelinks are pivotally mounted to bracket 70 and 72 so that grasping pad 74connected to brackets 70 will maintain a proper position for grasping asatellite while the arm members are moved.

A mechanism for moving the arm members to a grasping position includes aram power spring 76 disposed around tubular body 40. One end of the rampower spring abuts against a flange member 78 attached to the tubularbody 40 and the other end of the spring abuts a collar 80 that isslideably mounted on tubular body 40. Ram link 82 is composed of a smallrod 84 slidably mounted within tube 86. The purpose of the telescopingconstruction is to permit links 66 and 68 to fold forward for easystowage. During use of the device, rod 84 is immobilized in tube 86 by asuitable locking means (not shown). Shaft 84 is connected to link 66 bymeans of a collar 88, and tube 86 is mounted to a bracket 89 on collar80. The grasping arms are retained in a cocked position with the coilspring 76 compressed by means of a detent assembly 90 associated witheach grasping arm.

Each detent assembly comprises a pair of links 92 and 94 that are joinedtogether at one of their ends to form a pivotal joint 96. The other endsof links 92 and 94 are pivotally connected to brackets 98 and 100.Bracket 98 is fixed to tubular housing 40 and does not move whereasbracket 100 is attached to collar 80 which slides with respect totubular housing 40. It will be noted that one end of link 92 has a pin102 formed on the end thereof which connects to link 94 and this pinextends into the interior of housing 40 through an opening 104 formedtherein. The function of pin 102 is believed readily apparent and willbe discussed further hereafter. It will be noted that FIGURE 4illustrates the grasping arms in a cocked position and the links 92 and94 of the detent assembly have been bent through their longitudinal axisso that the force exerted thereon by the ram spring 76 tends to drivethe pivotal connection 96 and pin 102 into housing 40.

A trigger assembly 108 is slidably mounted in a tubular housing 40, butprojects therefrom for engagement with the object to be grasped. The endof the trigger assembly which projects from tubular housing 40 includesa contact button 110 for contact with the object to be grasped and atubular extension 112 that extends into the tubular housing. Extension112 terminates in a conical camming surface 114 that engages pins 102when the trigger assembly is pushed into housing 40 to cam pins 102outwardly and thus bend links 92 and 94 through their longitudinal axisand releases collar 80 so that it can be moved toward the grasping armsby spring 76. The trigger assembly is secured in housing 40 by a pin 116attached to housing 40 and slidable in a slot 118 formed in the tubularextension. The trigger assembly is biased by a trigger spring 120 to aposition wherein the camming surfaces 114 are not normally in engagementwith pins 102 of the detent assemblies.

The rotary rocket motor is mounted to a disc shaped member 122 attachedto flange 78. The motor includes a motor casing 124, a circular solidpropellant grain 126 of a suitable type, and a plurality of rocketnozzles 128 (normally three) mounted on the motor casing. The nozzlesare of course in communication with the interior of the motor casing. Anignition device (not shown) is included with the motor assembly forignition of the propellant grain after separation of the extensible boomand powerhead.

The operation of the despin device is as follows: An astronaut by meansof the extensible boom deploys the device toward a satellite to beretrieved and presses the trigger assembly of the powerhead against thesatellite being retrieved at its center of rotation. This causes thecamming surfaces 114 of the trigger assembly to cam the pins 102outwardly such that the detent assemblies are bent through theirlongitudinal axis to permit the ram power spring to continue bending ofthe linkage. When the linkage is bending the ram power spring alsoexerts pressure on the ram link which in turn transfers pressure to theparallel links of the grasping arms. The three grasping arms then rotateforward and inwardly, causing the three grasping pads to engage thesatellite as shown in FIGURE 2.

While the above action is taking place, end 42 of the extensible boomhas been pushed into tube 40 against the action of spring 58 to releasethe hooked end of handle hook to a position wherein the hook will notcatch pin 50 as the extensible boom is retracted or ejected from thetubular housing during separation of the extensible boom and thepowerhead. The rocket motor will then be ignited (by either a delayedfusing, radio ignition or any suitable means) after separation of theboom and powerhead to generate a thrust for stopping the rotation of thesatellite. The size and thrust of the rocket motor will be calculatedprior to use, taking into account the mass and rotational speed of thesatellie being retrieved. A remote radio operated release (not shown)can be provided that will free rocket motor disc 122 from housing 40when satellite rotation stops.

What is claimed is:

1. A satellite retrieval and despin device for use by an astronaut toretrieve a satellite, said device compising in combination:

a powerhead for grasping a rotating satellite in space;

and

an extensible boom means releasably connected to said powerhead formoving said powerhead from a remote position relative to the satelliteto a position adjacent the satellite;

said powerhead including:

a tubular body and a plurality of grasping arms pivotally mountedadjacent one end of said tubular body, each grasping arm comprising twoparallel links pivotally connected at one of their ends to a firstbracket mounted on said tubular body and pivotally connected at theirother ends to a second bracket, and a grasping pad connected to saidsecond bracket;

actuating means mounted on said tubular body and connected to saidgrasping arms for holding said grasping arms in a cocked position andmoving said grasping arms to a position of engagement with the satellitewhen released from a cocked position;

trigger means slidably mounted in said one end of said tubular body andin sliding engagement with said actuating means for releasing saidactuating means from a cocked position when said trigger means contactsa satellite to be grasped; and

a rocket motor mounted on the other end of said tubular body forrotating said powerhead about the longitudinal axis of said tubularbody;

said extensible means including:

a hand held mechanism comprising a spool of thin metal tape that formsitself into a tubelike boom when unrolled and drive means for rollingand unrolling said metal tape to vary the ength of the boom and thus theposition of said powerhead.

2. The satellite retrieval and despin device recited in claim 1 whereinsaid actuating means includes:

a coil spring mounted on said tubular body in a position so that one endthereof abuts said rocket motor and the other end engages a collarslidably mounted on said tubular body;

linkage means connected to said collar, the tubular body and saidgrasping arms, said linkage means being in a cocked position when thespring is compressed; and

said trigger means being mounted in said one end of said tubular body inproximity to said linkage whereby operation of said trigger means willrelease said linkage and permit movement of said grasping arms.

3. The satellite retrieval and despin device recited in claim 2 where insaid rocket motor mounted on the other end of said tubular body has anannular propellant grain.

4. The satellite retrieval and despin device recited in claim 2 whereinsaid hand held mechanism includes a manually operated crank means forrolling and unrolling said tape.

References Cited UNITED STATES PATENTS 406,546 7/1889 Taber 294-2,736,600 2/1956 Carlson 214-658 X 3,041,102 6/1962 Day 294110 3,268,0918/1966 Melton 2141 3,362,656 1/1968 Wyatt 2441 FERGUS S. MIDDLETON,Primary Examiner US. Cl. X.R. 29419, 110

